@Article{fister2013modified,<br />
 author= {I.~Fister and Xin-She Yang and J.~Brest and I.~Fister Jr.},<br />
 title={Modified firefly algorithm using quaternion representation},<br />
 journal={Expert Systems with Applications}, <br />
 year={2013},<br />
 volume={40},<br />
 issue={18},<br />
 pages={7220–7230},<br />
 doi={10.1016/j.eswa.2013.06.070}}